Systematic control of α-Fe₂O₃ crystal growth direction for improved electrochemical performance of lithium-ion battery anodes

Abstract

α-Fe2O3 nanomaterials with an elongated nanorod morphology exhibiting superior electrochemical performance were obtained through hydrothermal synthesis assisted by diamine derivatives as shape-controlling agents (SCAs) for application as anodes in lithium-ion batteries (LIBs). The physicochemical characteristics were investigated via XRD and FESEM, revealing well-crystallized α-Fe2O3 with adjustable nanorod lengths between 240 and 400 nm and aspect ratios in the range from 2.6 to 5.7. The electrochemical performance was evaluated by cyclic voltammetry and charge–discharge measurements. A SCA test series, including ethylenediamine, 1,2-diaminopropane, 2,3-diaminobutane, and N-methylethylenediamine, was implemented in terms of the impact on the nanorod aspect ratio. Varied substituents on the vicinal diamine structure were examined towards an optimized reaction center in terms of electron density and steric hindrance. Possible interaction mechanisms of the diamine derivatives with ferric species and the correlation between the aspect ratio and electrochemical performance are discussed. Intermediate-sized α-Fe2O3 nanorods with length/aspect ratios of ≈240 nm/≈2.6 and ≈280 nm/≈3.0 were found to have excellent electrochemical characteristics with reversible discharge capacities of 1086 and 1072 mAh g−1 at 0.1 C after 50 cycles.

Electrochemical Characteristics of Cobaltosic Oxide in Organic Electrolyte According to Bode Plots: Double‐Layer Capacitance and Pseudocapacitance

“…[9] Compared with double layer capacitance, the charge density stored with pseudocapacitance is several times higher. Among all sources, the pseudocapacitive contribution in transition metal oxides was not only demonstrated to show differential capacity (dQ/dV) curves [10] but also proven to become increasingly important, [3][4][5][11][12][13][14][15] which resulted in reversible capacities exceeding the theoretical value for Co 3 O 4 , [16][17][18][19][20][21][22][23][24][25] Fe 2 O 3 , [26][27][28][29][30] RuO 2 [31] and so forth. There are 3 possible sources for the capacities (charge storage) of electrode materials.…”

The Role of Pilot Lines in Bridging the Gap Between Fundamental Research and Industrial Production for Lithium‐Ion Battery Cells Relevant to Sustainable Electromobility: A Review

“…This section discusses challenges in upscaling of battery slurries from lab scale to the subsequent technological levels, primarily on examples of cathode slurries, because 1) investment and processing costs for cathode materials are significantly higher as for commonly utilized anode materials, such as graphite and its modified derivatives, and 2) the overall performance of a battery is largely defined by the cathode material, based on the lower capacity and poorer cycling stability compared with graphite that exhibits a high theoretical capacity of 372 mAh g −1 , given stoichiometry of LiC 6 . [ 45–47 ] Major cost drivers in cathode production are expensive precursor materials (often cobalt containing) and costly organic solvents for the slurry‐mixing process ( N ‐methyl‐2‐pyrrolidone [NMP]), associated with expensive exhaust removal systems and recovery processes. In contrast, environmentally friendly water as the solvent is being implemented for graphite‐based anode slurries.…”